Preheat oven to 400° and lightly butter a 2-quart soufflé dish.
In a 12-inch skillet, cook bacon over medium heat until crisp. Remove with a slotted spoon and drain on paper towels. Reduce heat to low; add onion and cook about 5 minutes, until translucent.
Add brussels sprouts and cook, stirring frequently until slightly soft, about 5 minutes. Transfer to a bowl and add reserved bacon, salt, pepper and pecans. Add potato slices to pan and cook until light brown, about 3 minutes per side.
Meanwhile, in a small bowl, whisk together maple syrup and butter.
Toss all ingredients together in soufflé dish and bake 20 minutes. Garnish with parsley and serve.
* Dark amber maple syrup is preferred (available online at www.bairdfarm.com).